Standardization works of international mobile telecommunication (IMT)-advanced which is a next generation (i.e., post 3rd generation) mobile communication system are carried out in the international telecommunication union radio communication sector (ITU-R). The IMT-advanced aims at support of an Internet protocol (IP)-based multimedia service with a data transfer rate of 1 Gbps in a stationary or slowly moving state or 100 Mbps in a fast moving state.
3rd generation partnership project (3GPP) is a system standard satisfying requirements of the IMT-advanced, and prepares LTE-advanced which is an improved version of long term evolution (LTE) based on orthogonal frequency division multiple access (OFDMA)/single carrier-frequency division multiple access (SC-FDMA) transmission. The LTE-advanced is one of promising candidates for the IMT-advanced. A technology related to a relay station is one of main technologies for the LTE-advanced.
A relay station (RS) is a device for relaying a signal between a base station (BS) and a user equipment (UE), and is used for cell coverage extension and throughput enhancement of a wireless communication system.
Many researches for a method of transmitting a signal between the BS and the RS are currently ongoing in the wireless communication employing the RS. A conventional method of transmitting a signal between the BS and the UE has a problem when a signal is transmitted between the BS and the RS.
In the conventional method of transmitting the signal between the BS and the UE, the UE transmits the signal through one entire subframe in a time domain. One reason of transmitting a signal by the UE through the entire subframe is to set a duration of each channel for transmitting a signal to the maximum extent possible in order to reduce instantaneous maximum power consumed by the UE.
However, there is a case where the RS cannot transmit or receive a signal through one entire subframe in the time domain. In general, the RS relays a signal with respect to a plurality of UEs, which results in frequent occurrence of switching between a reception (Rx) mode and a transmission (Tx) mode. Further, the RS can receive a signal from the BS or can transmit a signal to a relay UE at the same frequency band. Alternatively, the RS can receive a signal from the relay UE or can transmit a signal to the BS at the same frequency band. The switching between the Rx mode and the Tx mode requires a specific time (hereinafter referred to as a guard time) between an Rx-mode period and a Tx-mode period. During the guard time, the RS does not transmit or receive a signal in order to avoid inter-signal interference and to provide reliable operations. The guard time may be shorter than one symbol time.
As described above, a subframe in which the RS transmits or receives a signal may include a guard time. In this case, symbols included in a frequency band in which the RS transmits or receives a signal may have boundaries which are mismatched to that of a symbol of a frequency band in which a macro UE transmits or receives a signal. Orthogonality is not maintained when the symbol boundaries are mismatched, which may result in occurrence of interference.
In a wireless communication system employing an RS, a signal transmission and reception method and apparatus capable of decreasing interference is required when symbol boundaries are mismatched between a symbol of a frequency band allocated to the RS and a symbol of a frequency band allocated to a macro UE.